The U.S. dollar is the official currency of the United States and is represented by the symbol "$" or the code "USD." It is widely used in international trade and is considered a global reserve currency, meaning many countries hold it as part of their foreign exchange reserves. The dollar is subdivided into 100 smaller units called cents. The U.S. dollar is issued by the Federal Reserve, the central bank of the United States. It comes in various denominations, including coins and paper bills, with the most common bills being $1, $5, $10, $20, $50, and $100. The dollar's value can fluctuate based on economic factors, including inflation and interest rates.